1. Field of the Invention
The present invention relates to a stator structure for a rotary electric machine or motor. More specifically, the present invention relates a rotary electric machine or motor having a stator structure that is designed to curb decreases in output caused by magnetic flux leakage.
2. Background Information
Examples of rotary electric machines or motors are disclosed in Japanese Laid-Open Patent Publication No. 4-364343 and Japanese Patent Application No. 2000-379791. In these publications, the rotary electric machines have stators with the stator slots (groove parts that house the coils) being used as cooling medium passages so that the coils can be cooled directly in order to cool the rotary electric machine efficiently.
In the rotary electric machine of Japanese Laid-Open Patent Publication No. 4-364343, molds are arranged adjacent an inner peripheral surface of the stator and located within the axial slots of the stator core, and then an engineering plastic material is injected to fill the space defined by the stator core and the molds. Once the plastic material has hardened, the slot openings in the stator core are blocked by the plastic material so that axial cooling medium passages are formed in the stator core.
Meanwhile, in the rotary electric machine of Japanese Patent Application No. 2000-379791, a seal is formed on the outer surfaces of the plates arranged near the openings of the slots by filling this area with resin. Since it is not necessary to remove the plates after forming the seal, the problem of the magnetic steel plates that constitute the stator core being turned up and the stator core being damaged is eliminated.
In this kind of structure, it is necessary to provide a stopper on the side of each of the plates closest to the slot in order to prevent leakage of resin when the seal is formed. By providing the stopper, a reliable seal can be achieved and dimension management and the manufacturing process ate simplified because movement of the plates can be restricted.
In view of the above, there exists a need for an improved stator structure for use with a rotary electric machine. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
It has been discovered in the method disclosed in Japanese Laid-Open Patent Publication No. 4-364343 that removal of the molds from the stator core sometimes causes damage to the stator core. In particular, after the engineering plastic has been hardened, it is necessary to remove the molds from the area inside of the stator core and the areas inside of the slots of the stator core. Therefore, when the molds are removed from the areas inside of the slots of the stator core, there is the possibility that the thin magnetic steel plates that constitute the stator core will be pulled and turned up by the molds, thus damaging the stator core.
It has been further discovered in the method described in Japanese Patent Application No. 2000-379791 that a suitably large stopper is required to ensure the strength of the plates, the strength of the stopper, and the prevention of leakage of the material forming the seal. Magnetic flux leakage sometimes occurs through this large stopper. When this magnetic flux leakage occurs, the rotary electric machine (e.g., electric motor) experiences a decrease in output and torque.
Therefore, one object of the present invention is to provide a stator structure for a rotary electric machine that suppresses the magnetic flux leakage caused by the aforementioned stopper part and delivers efficient output.
In accordance with one aspect of the present invention, a rotary electric machine is provided that basically comprises a machine housing, a rotor and a stator. The machine housing has an interior area with a coolant inlet port and a coolant outlet port. The rotor is rotatably coupled within the interior area of the machine housing. The stator is fixedly coupled within the interior area of the machine housing and disposed around the rotor. The stator basically comprises a stator core, a plurality of protrusions, a plurality of plates and a seal. The stator core includes a plurality of circumferentially spaced tooth parts forming a plurality of slots between adjacent pairs of the tooth parts. The tooth parts have tips that define openings of the slots. The protrusions protrude from both lateral surfaces of the tips of the tooth parts into the slots. The coils are wound onto the tooth parts of the stator core and extending through the slots. The plates have recesses on circumferential sides with the protrusions of the adjacent pairs of the tooth parts being located in the recesses of the plates to block the openings of the slots. The seal is formed between rotor facing sides of the plates and the tooth parts.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.